Currently, most of network on-demand systems are network on-demand systems based on the C/S technique or those based on conventional P2P technique.
In a network on-demand system based on the C/S technique, a sever transfers data with a client via data transport protocols such as HTTP, RTSP, MMS, FTP, etc. A large amount of severs are required to support such on-demand system of a C/S (Master-slave) mode to share and distribute resources, which occupies a big bandwidth and requires a high cost for establishing a media resource station. Therefore, the effect of mass concurrent on-demand is not good.
The P2P technique overcomes shortcomings of the on-demand of a Master-slave mode, and can meet the requirements for mass on-demand from a streaming media. The P2P (Peer to Peer) technique, also called as point to point technical technique or peer-to-peer Internet work technique. Unlike the conventional C/S means, clients of users of P2P network may mutually provide resource including bandwidth, storage space and computation capacity between one another. In brief, it is possible to both download resources and upload resources, and the file interaction may be performed without support from servers. Although the network medium resource on-demand system based on this conventional P2P technique realizes a mass/a large-scale medium on-demand, and has advantages, such as fluent medium on-demand, low cost for establishing a resource station etc., the problems are inevitably encountered, as mentioned below. In particular, the more network resource consumed by medium files, the more prominent the problem seems to be.
Such peer-to-peer operation strategy of the conventional P2P technique excessively emphasizes the peer-to-peer operations of users, which results in the fact that all resources are equally returned back to users irrespective of the locations thereof in a network. The most severe result is that the network resources are wantonly used, and bandwidths in a same network are heavily occupied, even up to 50%˜80%, which results in the fact that the hardcore network is burden with a heavy transmission pressure, and the network may be blocked badly when other application programs access to the network. On the other hand, since considerable traffics are also exchanged between different networks in the P2P technique, hereby directly resulting in blocked traffics between different networks and generation of considerably-high running cost.